TABLE 1.

Results from the multivariable regression model to assess factors associated to antibiotic use

Variables	OR (95% CI)
Year of observation
2000	Reference
2010	1.02 (1.02–1.03)
2018	0.99 (0.98–0.99)
2019	0.91 (0.91–0.92)
Gender
Male	Reference
Female	1.28 (1.27–1.28)
Age groups (years)
40–49	Reference
50–59	1.00 (0.99–1.00)
60–69	1.08 (1.07–1.08)
70–79	1.02 (1.01–1.02)
80–89	0.93 (0.93–0.94)
90+	1.08 (1.07–1.09)
Local health units (Agenzie per la Tutela della Salute—ATS)
ATS Milano City	Reference
ATS Insubria	1.04 (1.04–1.05)
ATS Montagna	1.00 (0.99–1.01)
ATS Brianza	1.08 (1.07–1.08)
ATS Bergamo	1.10 (1.10–1.11)
ATS Brescia	1.24 (1.24–1.25)
ATS Val Padana	1.02 (1.02–1.03)
ATS Pavia	1.00 (0.99–1.00)
Polypharmacy (≥5 drugs)	2.57 (2.56–2.57)
Number of hospitalizations in the index year
0	Reference
1–3	1.86 (1.85–1.86)
>3	2.02 (2.01–2.03)

Abbreviations: R, odds ratio; CI, confidence interval.